This report sheds light on the potential climate benefits of the removal of fossil fuel production subsidies in terms of both greenhouse gas (GHG) emission reductions and the oil, gas and coal reserves that could become uneconomical to produce. The paper explains how different production subsidies currently unlock “zombie energy” from fossil fuel deposits that would not be commercially viable to produce without government support. It also presents new modelling of the global removal of certain subsidies to fossil fuel production.